Turbocharged and supercharged engines may be configured to compress ambient air entering the engine in order to increase power. Because compression of the air may cause an increase in temperature of the air, a charge air cooler may be utilized to cool the heated air thereby increasing its density and further increasing the potential power of the engine. If the humidity of the ambient air is high and or the engine is equipped with exhaust gas recirculation (EGR), however, condensation (e.g., water droplets) may form on any internal surface of the charge air cooler that is cooler than the dew point of the compressed air. During conditions such as a hard vehicle acceleration, these water droplets may be blown out of the charge air cooler and into the combustion chambers of the engine resulting in engine misfire, loss of torque and engine speed, and incompletely burned fuel, for example.
One approach for reducing the amount of condensation entering the combustion chambers is disclosed in US Patent Application Publication 2008/0190079. In the cited reference, a liquid trap for collecting condensation is placed in fluid communication with an air intake conduit downstream of the air cooler. The liquid trap may be coupled to a collection tank having a liquid level sensor which stores the collected condensation. The sensor may indicate when the water level becomes high and the collection tank needs to be emptied. Such a system may require a drain valve which may eventually stick closed or stick open causing a loss of boost pressure and subsequent loss of power to the engine. Such a system may also require the collection tank to be drained to the surroundings exterior to the vehicle. The condensation may contain regulated emissions, however, and draining the tank to the vehicle surroundings may not be an available option.
In one example, the issues described above may be addressed by a method comprising adjusting a drying air flow directed to a membrane in a charge air cooler in response to a condensate level in the charge air cooler. In this way, a charge air cooler condensate level may be maintained by applying a drying air flow to a membrane configured to selectively remove water. As one example, a drying air flow to a membrane may be increased in order to reduce a charge air cooler condensate level in order to prevent an engine cylinder misfire.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.